HYDROGEN is the most abundant element in the universe and yet, for a long time, it wasn鈥檛 thought to be particularly plentiful in its free form 鈥� as a reactive gas 鈥� here on Earth. Prospectors drilling for oil and methane sometimes discovered natural hydrogen in their wells, and it was found seeping out in odd places, such as the perpetual flames of Turkey鈥檚 Mount Chimaera. But most experts assumed that underground accumulations of naturally occurring hydrogen were small and rare.
Not any more. In the past couple of years, new detections of natural hydrogen and a better understanding of how it is generated have raised the prospect that Earth might contain vast stores of what some call 鈥済old hydrogen鈥�. Inevitably, that has led to a surge of excitement. The idea is that a ready natural supply of this clean-burning gas could transform our efforts to abandon fossil fuels. One widely cited estimate suggests there may be enough gold hydrogen beneath our feet to meet a lot of our energy demands for centuries.
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A clutch of ambitious start-ups is now engaged in a race to find deposits and figure out how best to extract the gas, as we report in our story 鈥淭he gold hydrogen rush: Does Earth contain near-limitless clean fuel?鈥�.
But as gold hydrogen fever takes hold, there are grounds for caution. Nearly everything about geologic hydrogen, to give it its proper name, remains uncertain, including exactly where it comes from, how much really exists and, crucially, what accumulations might be feasible to exploit. There would also be challenges regarding storage and transport, and worries over the environmental and social costs of a hydrogen-drilling infrastructure.
To overcome some of the uncertainties, at least one company is proposing to inject water and heat into rocks underground to produce hydrogen, in a process roughly akin to fracking. But that comes with other risks, of course. And for all the hype, hydrogen hunters have yet to make a find of the magnitude we are hoping for.
Until they do, and until we know for sure that hydrogen extraction is scalable, we should see it for what it is: an exciting prospect, but with many unknowns.
